JPH08315096A - Magnetic recording medium and method for judging its authenticity - Google Patents

Abstract

PURPOSE: To provide a magnetic recording medium such as a magnetic card of which fogery or alteration is not easy though its production is easy and an authenticity judging method capable of easily and accurately judging the authenticity of the medium. CONSTITUTION: A magnetic recording layer 12 and a magnetic shielding layer 14 with high magnetic permeability are successively laminated on a card base material 11, a pattern material 17 having permeability different from that of the layer 14 is irregularly dispersed on the whole surface between both the layers 12, 14 and the dispersed pattern material 17 is constituted as a random pattern part 13. A part of the layer 14 is read out by a magnetic head 15, the read signal 16 is digitally registered in the layer 12 as collating digital information, and at the time of using the card, similarly read digital signal 15 compared with the collating digital information to judged the authenticity of the card.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a commuter pass, an admission ticket, a prepaid card, a credit card, a cash card,
The present invention relates to a magnetic recording medium used for various securities, ID cards for identification cards, and the like, and more particularly to technology for preventing forgery and falsification of this magnetic recording medium.

[0002]

2. Description of the Related Art In recent years, the so-called card type magnetic recording medium (magnetic card) as described above has become widespread. This magnetic recording medium has a magnetic recording layer in which magnetic recording is written, and on this magnetic recording layer, various information (for example, ID information, information about money, etc.) according to the usage target is written on a magnetic head or the like. The information written by the writing means is read by a magnetic head or the like. By the way, when using such a card, whether the card itself is valid or not,
It is becoming more and more necessary to determine whether the user has the right to use the card and prevent the card from being misused.

Among the countermeasures against abuse, in order to determine whether the card itself is forged or tampered with, a magnetic recording layer is formed of a material having a high coercive force, a magnetic shield is formed on the magnetic recording layer, and a magnetic recording layer is formed. Means such as marking with a special ink on a recording layer and sticking a hologram foil on a card have been implemented. Further, regarding whether or not the person who uses the card has the proper authority, a method of inputting a personal identification number or comparing a signature written on the card with a signature written at the time of use is adopted.

However, even with the above-mentioned means and methods for confirming the authenticity of a card, it cannot be said to be reliable at present. Therefore, as disclosed in Japanese Unexamined Patent Publication No. 63-501250, authenticity determination information in which a metal fiber such as stainless steel is unevenly distributed and embedded in a document is recorded.
A technique has been developed in which the authenticity of the card is determined by irradiating the document with microwaves to read the pattern of the metal fiber.

[0005]

When the technique described in the above publication is applied to a card or the like which is a magnetic recording medium, the metal fiber is dispersed and embedded in plastic or paper, but the metal fiber itself. Is expensive,
Since the cutting process is not easy and it is difficult to disperse because it agglomerates and aggregates due to static electricity when embedded in a document, the manufacturing cost rises.

[0006] Further, in the authenticity determination by irradiation of microwaves, specifically, information specific to the pattern is obtained by transmitting / reflecting the microwave to / from the pattern of the metal fiber, and this information is approximated to the correlation coefficient. However, in this case, it is extremely difficult to set the correlation coefficient in order to enable highly accurate true / false determination, so that it is difficult to control the microwave and a reading error occurs, which makes it practical. In addition to this, there is a concern that the reading device itself may become complicated and large due to microwaves.

The present invention has been made in view of the above circumstances, is highly safe against forgery or tampering, is easy and inexpensive to manufacture, and allows authenticity determination information to be read by a relatively simple device. Further, it is an object of the present invention to provide a magnetic recording medium and a method of authenticating the magnetic recording medium which can easily control a unique non-uniform pattern for preventing forgery / falsification and authenticity determination.

[0008]

The present invention has been made to achieve the above object, and a magnetic recording medium according to claim 1 has a magnetic recording layer and a magnetic shielding layer on a substrate. A random pattern portion, which is sequentially provided in order, and in which a pattern material having a magnetic permeability different from that of the magnetic shield layer is non-uniformly dispersed is provided at least at a part between the magnetic recording layer and the magnetic shield layer. Is characterized by.

According to a second aspect of the present invention, there is provided the magnetic recording medium according to the first aspect, wherein the random pattern portion is provided by a printing method.

A third aspect of the present invention is the authenticity determination method for a magnetic recording medium according to the first aspect, wherein a part of the magnetic shield layer is read as a magnetic track by a magnetic sensor. An analog signal peculiar to the magnetic recording medium is obtained, and the analog signal is converted into a digital signal and digitally registered in the magnetic recording layer as digital information for collation. It is characterized in that the digital information is read and digitally converted, and the digital information is collated with the previously registered digital information for collation.

[0011]

According to the magnetic recording medium of the first aspect of the present invention, the information peculiar to the medium is provided by the random pattern portion without impairing the magnetic shielding effect of the magnetic shielding layer, and the random pattern portion is different for each medium. By doing so, individualization can be achieved for each medium. By forming the random pattern portion by non-uniformly dispersing the magnetic shield layer and the pattern material having different magnetic permeability between the base material and the magnetic shield layer,
A magnetic recording medium that is difficult to forge or falsify can be manufactured relatively easily and inexpensively.

According to the magnetic recording medium of the second aspect of the present invention, by forming the random pattern portion by a printing method, the random pattern portion can be accurately formed, and the magnetic recording medium can be manufactured more easily. And it will be cheaper.

According to the authenticity determination method for a magnetic recording medium according to claim 3 of the present invention, it is extremely difficult to forge or falsify information for collation, and the accuracy and reproducibility of the authenticity determination are excellent. As a result, it is possible to provide a more secure magnetic recording medium.

[0014]

【Example】

A. One Embodiment (1) Configuration FIGS. 1 to 3 show a magnetic card 10 which is a magnetic recording medium according to one embodiment of the present invention. This magnetic card 10 has a three-layer structure in which a magnetic recording layer 12 is provided on a card base material 11, and a magnetic shielding layer 14 made of a magnetic material having a relatively high magnetic permeability is provided on the magnetic recording layer 12. And a magnetic recording layer 12 and a magnetic shield layer 14
The random pattern portion 13 in which the pattern material 17 having a magnetic permeability different from that of the magnetic shield layer 14 is nonuniformly dispersed is formed over the entire surface between and.
As shown in FIG. 3, the random pattern portion 13 includes the image area 13a of the pattern material 17 and the other non-image area 13b.
Composed of and.

FIG. 4 shows another example of the magnetic card 10 having a random pattern portion different from that of the magnetic card 10 shown in FIG. The pattern material 17 forming the random pattern portion 13 of the magnetic card 10 is fine in the form of fine particles, and is composed of the image area 13c and the non-image area 13d.

The magnetic card 10 shown in FIG.
In another example of the magnetic card having a different configuration, the magnetic material 14a forming the magnetic shield layer 14 in this case is a scale-like one for the purpose of enhancing the magnetic shield effect.

The card base material 11 is formed into a card shape having a predetermined shape and dimensions, and its material is, for example, plastics such as polyethylene terephthalate (PET), polyvinyl chloride, polystyrene, paper, synthetic paper and the like. Can be used alone or as a complex.

As the magnetic material of the magnetic recording layer 12,
Powders of metals and alloys such as magnetite, γ-iron oxide, Co-deposited γ-iron oxide, barium ferrite, strontium ferrite, and chromium dioxide can be used, but those with a coercive force of 600 Oe or more are used because of the stability of information. It is preferably used. It is generally cost-effective to form the magnetic recording layer 12 directly on the base material by a wet coating method, but since it is partially provided on the base material by a dry coating method such as vapor deposition or sputtering. If so, use the printing method. Further, in addition to the method of directly providing it on the base material, it may be provided by a transfer method.

The magnetic material of the magnetic shield layer 14 is Fe, Ni, Mn-Zn ferrite, which is a high magnetic permeability material.
Powders of metals and alloys such as Ni-Zn ferrite, Mn ferrite, Zn ferrite, silicon steel, permalloy, sendust, alperm, and permendur, and metal compounds can be used. To enhance the magnetic shield effect, please refer to FIG.
It is desirable to use a scale-like material such as the magnetic card 10 to facilitate the flow of magnetic force lines in the surface. The particle diameter is 2 μm or more and 100 μm or less, and the scale thickness is 2 μm.
It is desirable to use magnetic particles having a size of m or less. If the magnetic particles are too small, the magnetic shield effect deteriorates, and the level of the random reproduction output waveform read by a magnetic sensor such as a magnetic head becomes low, resulting in a poor S / N ratio and poor reproducibility of information. The printed / applied coating has severe irregularities, making it impractical. Magnetic shield layer 1
Although 4 may be possible with a thin film such as vapor deposition or sputtering, generally, the above magnetic material is often made into a coating material and wet-coated. In the present invention, the purpose is to form uneven distribution of the magnetic material forming the magnetic shield layer 14, and it is desirable that the wet application surface has leveling when wet coating is performed. For that purpose, a blade coating method or a knife coating method is used. Law,
The post-measurement method such as the reverse roll method is preferably adopted.

As the pattern material 17, for example,
The initial permeability of the magnetic shielding layer is 8000, and the maximum permeability is 10,000.
If 78 Permalloy of No. 7 is used, a magnetic material having a magnetic permeability other than that can also be used, but if a non-magnetic material is used, uneven distribution of the magnetic material forming the magnetic shield layer 14 can be most effectively created. it can. For that purpose, images having different thicknesses, areas, and patterns are provided as irregularly as possible by a printing method such as gravure, screen or offset using a printing ink or a printing medium using an ordinary non-magnetic pigment. Is desirable.

The card substrate 11 and the magnetic recording layer 12
And a polymeric binder as a printing ink and a magnetic paint for forming a three-layer structure composed of the magnetic shielding layer 14,
Polyester resin, acrylic resin, vinyl chloride / vinyl acetate copolymer, urethane resin, phenol resin, epoxy resin, urea resin, nitrified cotton and the like can be used. In the case of screen ink, the solvent used is cyclohexanone, xylene, MIBK, isophorone, petroleum-based, alcohol-based solvent having a boiling point of 110 ° C or higher, and for gravure ink, toluene, MEK, acetone, ethyl acetate, acetic acid. An organic solvent having a relatively low boiling point such as butyl, petroleum-based or alcohol-based is used. In the case of offset ink, a high boiling point solvent such as linseed oil is generally used. Further, if necessary, it is desirable to mix an appropriate amount of a dispersant, a defoaming agent, and an extender pigment to improve the properties as an ink.

(2) Judgment of authenticity of magnetic card For example, assuming that the magnetic card 10 is applied to a cash card, a method for judging whether the cash card is true or false will be described. Since the magnetic card 10 is provided with the random pattern portion 13, the unique information is added, and then this unique information is registered in the magnetic recording layer 12. For that purpose, first, a known magnetic sensor such as a magnetic head or a magnetoresistive sensor is used to form the magnetic shield layer 1.
4 is read as a magnetic track, and this unique information (output waveform) is obtained as an analog signal unique to the magnetic card 10. Next, this analog signal is A / D converted and converted into digital information of, for example, 8 bytes. The digital information thus obtained is used as collation digital information, and the magnetic recording layer 1
The information is registered in a digital information recording unit (not shown) provided in FIG.
FIG. 5 shows the bias coil 15 a and the reading coil 1.
A magnetic card 15 for reading and reproducing, provided with 5b, and a magnetic card 1 using a scale-like magnetic material for the magnetic shield layer 14.
It shows a state in which the unique information 16 of 0 is being read.

When using the magnetic card 10, first, a part of the magnetic shield layer 14 is read as a magnetic track by the magnetic sensor and converted into, for example, 8-byte digital information. Next, the correlation between the converted digital information and the matching digital information registered in the digital information recording unit in advance is compared and calculated. FIG. 6 shows a case where the correlation coefficient between the verification digital information and the digital information read and converted this time is equal to or greater than a predetermined threshold value. In this case, the magnetic card 10 is determined to be authentic and desired by the user. You can make a deal.

Next, considering the case where the magnetic card 10 is forged or falsified, the output waveform read from the magnetic shield layer 14 of the forged or falsified magnetic card is registered as shown in FIG. The output waveform of the verification digital information is very different. Therefore, when the read output waveform is converted into digital information of 8 Bytes and the correlation coefficient with the digital information registered in advance is calculated, it is significantly lower than the predetermined threshold value, and as a result, the magnetic card 10 is determined to be a fake. Trading is prohibited.

B. Manufacturing Example Next, a plurality of actually manufactured magnetic cards according to the present invention will be described. [Manufacturing Example 1] The magnetic card 10 shown in FIG. 1 was manufactured as follows. On a white card substrate 11 made of synthetic paper having a thickness of 250 μm, a magnetic recording layer coating composition having the following “composition 1a” was provided by a gravure method so that the coating thickness after drying was 12 μm. It was Furthermore, “Composition 1
The printing ink for gravure consisting of “b” was used to endlessly make a random pattern as shown in FIG.
Random pattern portion 1 in which winding printing is performed with a 175 line / inch gravure plate and magnetite magnetic powder having a film thickness of 1 to 4 μm and an initial magnetic permeability of 160 is used as the pattern material 17.
3 is provided. Further, the magnetic shielding layer 14 made of a high-permeability magnetic material of “composition 1c” has an average film thickness after drying of 15 μm.
The reverse roll method was applied so as to obtain m, to prepare a roll original roll for a magnetic card. This was cut into sheets and cut out into a card shape to obtain a magnetic card 10.

Magnetic recording layer 12- “Composition 1a” Magnetic material: Barium ferrite (coercive force 2750 Oe) 100 parts by weight Surfactant: Garfac (manufactured by Toho Chemical Co., Ltd.) 3 parts by weight Polymer binder: Urethane resin (N2304) : Made by Nippon Polyurethane Co., Ltd.) 50 parts by weight: Chlorinated vinyl acetate resin (Eslec A: Sekisui Chemical Co., Ltd.) 18 parts by weight Organic solvent: MEK / toluene = 1/1 60 parts by weight

Random pattern part 13- “Composition 1b” Pattern material 17 (magnetic material): Magnetite (initial magnetic permeability 160) 100 parts by weight Surfactant: Garfac (manufactured by Toho Kagaku) 2 parts by weight Polymer binder : Polyester resin Byron 200 (manufactured by Toyobo Co., Ltd.) 30 parts by weight Organic solvent: MEK / toluene = 1/1 60 parts by weight

Magnetic shielding layer 14- “Composition 1c” High permeability magnetic material (magnetic powder): Mn—Zn ferrite (initial permeability 1800) 100 parts by weight Surfactant: Garfac (manufactured by Toho Kagaku Co., Ltd.) 2 parts by weight Part Polymer binder: Polyester resin Byron 180 (manufactured by Toyobo Co., Ltd.) 30 parts by weight Organic solvent: MEK / toluene = 1/1 60 parts by weight

[Manufacturing Example 2] The magnetic card 10 shown in FIG.
Was produced as follows. On a white card substrate 11 made of polyethylene terephthalate (PET) having a thickness of 188 μm, a magnetic recording layer coating material having the following “composition 2a” was formed by a gravure method to obtain a magnetic recording layer 12. Next, the printing ink for gravure composed of “composition 2b” was wound and printed by a gravure plate having a plate depth of 150 μm and 200 lines / inch in which a random pattern as shown in FIG. 4 was endlessly printed, and the film thickness was 1 to 4 μm. The random pattern portion 13 having the non-magnetic material as the pattern material 17 was provided. Further, a magnetic shielding layer 14 made of a high-permeability magnetic material of “composition 2c” was applied by a blade coating method so that the average film thickness after drying was 15 μm, to prepare a roll raw material for a magnetic card. . This was cut into sheets and cut out into a card shape to obtain a magnetic card 10 shown in FIG.

Magnetic recording layer 12- “Composition 2a” Magnetic material: barium ferrite (coercive force 1750 Oe) 100 parts by weight Surfactant: Garfac (manufactured by Toho Chemical Co., Ltd.) 3 parts by weight Polymer binder: urethane resin (N2304) : Made by Nippon Polyurethane Co., Ltd.) 50 parts by weight: Chlorinated vinyl acetate resin (Eslec A: Sekisui Chemical Co., Ltd.) 18 parts by weight Organic solvent: MEK / toluene = 1/1 60 parts by weight

Random pattern portion 13- “Composition 2b” Pattern material 17 (non-magnetic material): carbon black (colored carbon) 20 parts by weight Surfactant: Garfac (manufactured by Toho Chemical Co., Ltd.) 3 parts by weight Polymer binder : Polyester resin Byron 200 (manufactured by Toyobo Co., Ltd.) 30 parts by weight Organic solvent: MEK / toluene = 1/1 60 parts by weight

Magnetic shielding layer 14- “Composition 2c” High permeability magnetic material (magnetic powder): 78 Permalloy (initial permeability 8300, scale-like) 100 parts by weight Surfactant: Garfac (manufactured by Toho Chemical Co., Ltd.) 2 Parts by weight Polymer binder: Polyester resin Byron 180 (manufactured by Toyobo Co., Ltd.) 30 parts by weight Organic solvent: MEK / toluene = 1/1 60 parts by weight

Next, a plurality of comparative examples manufactured for comparison with the above-mentioned manufacturing examples 1 and 2 will be described. [Comparative Example 1] In the magnetic card 10 of Production Example 1,
Without providing the random pattern portion 13 made of the pattern material 17 which is the magnetite magnetic powder having the initial magnetic permeability of 160, the magnetic recording layer 12 and the composition “1” according to the above “composition 1a” are provided.
Only the magnetic shielding layer 14 made of a high magnetic permeability magnetic material according to “c” was provided on the card base material 11 to prepare a roll original roll for a magnetic card. This was cut into sheets and cut into cards to obtain magnetic cards.

[Comparative Example 2] Magnetic Card 1 of Manufacturing Example 2
0, without providing the random pattern portion 13 made of the pattern material 17 which is a non-magnetic material, the composition 2
Only the magnetic recording layer 12 of “a” and the magnetic shielding layer 14 of the high magnetic permeability magnetic material of the composition “2c” were provided on the card substrate 11 to prepare a roll stock for a magnetic card. This was cut into sheets and cut into cards to obtain magnetic cards.

For a total of four types of magnetic cards of Manufacturing Examples 1 and 2 and Comparative Examples 1 and 2, a part of the magnetic shield layer 14 was read by the magnetic head 15 as a magnetic track. Specifically, the specifications of the magnetic head 15 are as follows: Sendust read coil of about 400 turns and write coil of about 1
A 500-turn two-winding read / playback magnetic head (effective track width 4 mm, core gap 200 μm) was used, and read at a write bias current of 50 mA to obtain an analog output voltage signal unique to each card.
The N ratio and the waveform reproducibility were evaluated. The S / N ratio represents the ratio between the DC noise and the output waveform when the average steeple output level when the slice level of the output waveform is set to 30% of the maximum peak voltage is used as the signal, and the larger the value, the more the signal fluctuation. Less desirable. The waveform reproducibility was evaluated using the correlation coefficient of each output waveform after the read signal was digitally processed by determining the resolution and sampling period.

Table 1 summarizes each measured value and evaluation,
As is clear from Table 1, Production Example 1 according to the present invention,
As compared with 2, the identification of Comparative Examples 1 and 2 in which the random pattern portion 13 does not exist is unstable and the autocorrelation coefficient is inferior, while the Production Examples 1 and 2 are excellent in S / N ratio and reproducibility, Moreover, the magnetic shield effect was as good as in Comparative Examples 1 and 2, and a magnetic card having unique information suitable for practical use was obtained.

[0037]

[Table 1]

[0038]

As described above, according to the magnetic recording medium of the present invention, the information peculiar to the medium is added by the random pattern portion without impairing the magnetic shielding effect of the magnetic shielding layer. By making the random pattern part different for each medium, uniqueization can be achieved for each medium, so it is highly effective in preventing forgery or tampering.
If the random pattern portion is formed by a printing method, the random pattern portion can be accurately formed and the magnetic recording medium itself can be easily and inexpensively manufactured.

Further, according to the authenticity determination method of the magnetic recording medium of the present invention, it is extremely difficult to forge or falsify the information for collation, and the accuracy and reproducibility of the authenticity determination are excellent. It is possible to provide a more secure magnetic recording medium.

[Brief description of drawings]

FIG. 1 is a plan view of a magnetic card according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II-II of FIG.

3 is a sectional view taken along the line III-III of FIG.

FIG. 4 is a plan view of a magnetic card according to a modified example of the embodiment.

FIG. 5 is a side sectional view of a magnetic card of another modified example of the embodiment and a diagram showing a state in which unique information of the magnetic card is being read by a magnetic head.

FIG. 6 is a diagram showing information processing when a genuine magnetic card is collated.

FIG. 7 is a diagram showing information processing when collating a forged or altered magnetic card.

[Explanation of symbols]

10 ... Magnetic card (magnetic recording medium), 11 ... Card base material, 12 ... Magnetic recording layer, 13 ... Random pattern part, 1
4 ... Magnetic shielding layer, 15 ... Magnetic head (magnetic sensor), 1
6 ... Unique information, 17 ... Pattern material.

Claims (3)

[Claims] 1. A magnetic recording layer and a magnetic shielding layer are sequentially provided on a base material in this order, and at least a part between the magnetic recording layer and the magnetic shielding layer has a magnetic permeability different from that of the magnetic shielding layer. A magnetic recording medium comprising: a random pattern portion in which a pattern material having the above is unevenly dispersed. 2. The magnetic recording medium according to claim 1, wherein the random pattern portion is provided by a printing method. 3. The authenticity determination method for a magnetic recording medium according to claim 1, wherein a part of the magnetic shield layer is read as a magnetic track by a magnetic sensor and is unique to the magnetic recording medium. Obtain an analog signal, convert this analog signal to a digital signal, and digitally register it as verification digital information in the magnetic recording layer, and in use, read a part of the shielding layer in the same manner and perform digital conversion. A method for determining authenticity of a magnetic recording medium, characterized in that the digital information is matched with the matching digital information registered in advance.